Assault is a serious accusation. It's a crime in which one person threatens harm to another in a convincing manner. Assault itself is not the act of violence; that's called battery. Battery is unlawful conduct of a physical nature. It can be unwelcome sexual contact or acts of violence.
Not all threats are considered to be assaults, so if you've been accused of assault, you can use that to your advantage. Threats intending to cause apprehension or threats that do cause apprehension are assault. That means that the person you're threatening needs to truly fear for his or her safety.